U.S. patent number 5,159,014 [Application Number 07/409,293] was granted by the patent office on 1992-10-27 for thermoplastic elastomer composition and rubber parts of refrigerator having a layer composed of thermoplastic elastomer composition.
This patent grant is currently assigned to Japan Synthetic Rubber Co., Ltd.. Invention is credited to Mamoru Hasegawa, Akihiko Morikawa, Noboru Oshima, Fumio Tsutsumi.
United States Patent |
5,159,014 |
Tsutsumi , et al. |
October 27, 1992 |
Thermoplastic elastomer composition and rubber parts of
refrigerator having a layer composed of thermoplastic elastomer
composition
Abstract
A thermoplastic elastomer composition comprising (a) 20 to 70
parts by weight of a polyamide and (b) 80 to 30 parts by weight of
a butyl rubber modified with a functional-group-containing compound
having at least one group selected from a carboxyl group, an acid
anhydride group and an epoxy group as the functional group, the
total amount of the (a) and (b) components being 100 parts by
weight. The thermoplastic elastomer composition is resistant to
permeation of FREON gases containing hydrogen atom in their
molecules and has excellent flexibility, low-temperature resistance
and oil resistance.
Inventors: |
Tsutsumi; Fumio (Yokkaichi,
JP), Morikawa; Akihiko (Yokkaichi, JP),
Hasegawa; Mamoru (Yokkaichi, JP), Oshima; Noboru
(Suzuka, JP) |
Assignee: |
Japan Synthetic Rubber Co.,
Ltd. (Tokyo, JP)
|
Family
ID: |
16960482 |
Appl.
No.: |
07/409,293 |
Filed: |
September 19, 1989 |
Foreign Application Priority Data
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Sep 20, 1988 [JP] |
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63-233782 |
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Current U.S.
Class: |
525/66;
525/179 |
Current CPC
Class: |
C08L
23/26 (20130101); C08L 51/06 (20130101); C08L
77/00 (20130101); C08L 23/26 (20130101); C08L
51/06 (20130101); C08L 77/00 (20130101); C08L
77/00 (20130101); C08L 77/00 (20130101); C08L
2666/20 (20130101); C08L 2666/14 (20130101); C08L
2666/04 (20130101); C08L 2666/24 (20130101); C08L
2666/24 (20130101) |
Current International
Class: |
C08L
23/00 (20060101); C08L 23/26 (20060101); C08L
51/00 (20060101); C08L 51/06 (20060101); C08L
77/00 (20060101); C08L 077/00 () |
Field of
Search: |
;525/66,179 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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|
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57-070139 |
|
Apr 1982 |
|
JP |
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63-221182 |
|
Sep 1988 |
|
JP |
|
63-238159 |
|
Oct 1988 |
|
JP |
|
1518639 |
|
Jul 1978 |
|
GB |
|
1552352 |
|
Sep 1979 |
|
GB |
|
Primary Examiner: Carrillo; Ana L.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt
Claims
What is claimed is:
1. A thermoplastic elastomer composition having excellent
flexibility and balance of oil resistance, low-temperature
resistance, and resistance to permeation by fluorocarbons,
consisting essentially of;
(a) 20 to 70 parts by weight of a polyamide, and
(b) 80 to 30 parts by weight of a butyl rubber modified with from 1
to 50 milliequivalents per 100 grams of said butyl rubber of a
member selected from the group consisting of
.alpha.,.beta.-ethylenically unsaturated carboxylic acids;
.alpha.,.beta.-ethylenically unsaturated carboxylic anhydrides;
glycidyl esters of .alpha.,.beta.-ethylenically unsaturated
carboxylic acids; and alkenyl glycidyl ethers, the total amount of
the (a) and (b) components being 100 parts by weight.
2. The thermoplastic elastomer composition according to claim 1,
wherein the polyamide (a) is a member selected from the group
consisting of nylon 6, nylon 6,6, nylon 11, nylon 12, nylon 6,9,
nylon 6,10, nylon 4,6 and nylon 1,12.
3. The thermoplastic elastomer composition according to claim 1,
wherein the polyamide (a) is nylon 11, nylon 12, nylon 6 or nylon
4,6.
4. The thermoplastic elastomer composition according to claim 1,
wherein the polyamide (a) is nylon 11 or nylon 12.
5. The thermoplastic elastomer composition according to claim 1,
wherein the butyl rubber (b) is that prepared by
dehydrohalogenating a halogenated butyl rubber with a
dehydrohalogenating agent to prepare a conjugated diene
unit-containing butyl rubber and then subjecting the conjugated
diene unit-containing butyl rubber to addition reaction in the
absence of a peroxide catalyst with a functional group-containing
compound selected from the group consisting of
.alpha.,.beta.-ethylenically unsaturated carboxylic acids;
.alpha.,.beta.-ethylenically unsaturated dicarboxylic anhydrides;
glycidyl esters of .alpha.,.beta.-ethylenically unsaturated
carboxylic acids; and alkenyl glycidyl ethers.
6. The thermoplastic elastomer composition according to claim 1,
wherein the amount of the polyamide (a) is 25 to 60 parts by weight
and the amount of the butyl rubber (b) is 75 to 40 parts by
weight.
7. The thermoplastic elastomer according to claim 1, wherein the
amount of the polyamide (a) is 30 to 55 parts by weight and the
amount of the butyl rubber (b) is 70 to 45 parts by weight.
8. A thermoplastic elastomer composition according to claim 1,
wherein the .alpha.,.beta.-ethylenically unsaturated carboxylic
acids are selected from the group consisting of maleic acid,
acrylic acid, methacrylic acid, itaconic acid, monoethyl maleate,
fumaric acid, monoethyl fumarate, vinylbenzoic acid, vinylphthalic
acid, monoethyl itaconate and maleic monoamilide; the
.alpha.,.beta.-ethylenically unsaturated dicarboxylic anhydrides
are selected from the group consisting of maleic anhydride,
itaconic anhydride, and vinylphthalic anhydride; the glycidyl
esters of .alpha.,.beta.-ethylenically unsaturated carboxylic acids
are selected from the group consisting of glycidyl methacrylate,
glycidyl acrylate, monoglycidyl itaconate and diglycidyl itaconate;
and the alkenyl glycidyl ethers are selected from the group
consisting of allyl glycidyl ether and vinyl glycidyl ether.
9. A thermoplastic elastomer composition having excellent
flexibility and balance of oil resistance, low-temperature
resistance, and resistance to permeation by fluorocarbons,
consisting essentially of:
(a) 20 to 70 parts by weight of nylon 11, and
(b) 80 to 30 parts by weight of a butyl rubber modified with from 1
to 50 milliequivalents per 100 grams of said butyl rubber of a
member selected from the group consisting of
.alpha.,.beta.-ethylenically unsaturated carboxylic acids;
.alpha.,.beta.-ethylenically unsaturated dicarboxylic anhydrides;
glycidyl esters of .alpha.,.beta.-ethylenically unsaturated
carboxylic acids; and alkenyl glycidyl ethers, the total amount of
the (a) and (b) components being 100 parts by weight.
10. A thermoplastic elastomer composition according to claim 9,
wherein the .alpha.,.beta.-ethylenically unsaturated carboxylic
acids are selected from the group consisting of maleic acid,
acrylic acid, methacrylic acid, itaconic acid, monoethyl maleate,
fumaric acid, monoethyl fumarate, vinylbenzoic acid, vinylphthalic
acid, monoethyl itaconate and maleic monoanilide; the
.alpha.,.beta.-ethylenically unsaturated dicarboxylic anhydrides
are selected from the group consisting of maleic anhydride,
itaconic anhydride, and vinylphthalic anhydride; the glycidyl
esters of .alpha.,.beta.-ethylenically unsaturated carboxylic acids
are selected from the group consisting of glycidyl methacrylate,
glycidyl acrylate, monoglycidyl itaconate and diglycidyl itaconate;
and the alkenyl glycidyl ethers are selected from the group
consisting of allyl glycidyl ether and vinyl glycidyl ether.
Description
This invention relates to a thermoplastic elastomer composition
which is rich in flexibility and excellent in balance of oil
resistance, low-temperature resistance and resistance to permeation
of FREON gases (fluorocarbons) and the like, and particularly to a
thermoplastic elastomer composition suitable for use in rubber
parts of a refrigerator.
As a refrigerant for air-conditioner in automobiles, FREON gases
R-12(CCl.sub.2 F.sub.2) , R-11(CCl.sub.3 F) and R-113(CCl.sub.2
F-CCl.sub.2 F) have heretofore been generally used. However,
recently, it has been clarified that FREON gases R-12, R-11 and
R-113 break the ozonosphere in the upper atmosphere and regulation
of use of FREON gases R-12, R-11 and R-113 is being internationally
strengthened.
As a countermeasure therefor, the change of the refrigerant from
FREON gases R-12, R-11 and R-113 to CF.sub.4 and easily
decomposable FREON gases containing hydrogen atom in their
molecules (hereinafter referred to as hydrogen-containing FREON
gases) such as FREON gases R-22(CHClF.sub.2), R-142b(CH.sub.3
CClF.sub.2), R-134a(CF.sub.3 CH.sub.2 F), R-123(CF.sub.3
CHCl.sub.2), R-152a(CH.sub.3 CHF.sub.2), R-141b(CH.sub.3 CCl.sub.2
f), R-133a(CF.sub.3 CH.sub.2 Cl), R-143a(CH.sub.3 CF.sub.3) and the
like is in progress.
However, hydrogen-containing FREON gases such as FREON gases R-22,
R-142b, R-134a and the like have a greater permeation ability to a
material consisting of an elastomer than FREON gas R-12 and the
like, and vulcanized rubbers comprising a nitrile rubber as a main
component which have conventionally been used for FREON gas R-12
and the like are not satisfactory in ability to seal
hydrogen-containing FREON gases R-22, R-142b, R-134a and the
like.
Therefore, use of a metal tube for hydrogen-containing FREON gases
such as FREON gases R-22, R-142b, R-134a and the like is taken into
consideration; however, this has such problems that noise is made
by vibration during the running of a car and the degree of freedom
of piping layout in a bonnet is reduced.
Also, the use of resin hoses consisting essentially of nylon is
under consideration; however, there are problems similar to those
in the case of use of a metal tube. Therefore, there has been
desired development of a rubber material for sealing FREON gases
which has flexibility and excellent resistance to permeation of
hydrogen-containing FREON gases such as FREON gases R-22, R-142b,
R-143a and the like.
In addition, attempts have been made to blend a flexible elastomer
with a resin such as nylon to obtain a balance of resistance to
FREON gas-permeation and flexibility; however, when a satisfactory
flexibility has been achieved the resistance to FREON
gas-permeation has become insufficient and when satisfactory
resistance to FREON gas-permeation has been achieved the
flexibility has become insufficient. Thus, it has been difficult to
satisfy the two properties simultaneously.
An object of this invention is to provide a thermoplastic elastomer
composition having a flexibility and excellent resistance to
permeation of FREON gases containing hydrogen atom in their
molecules such as FREON gases R-22, R-142b, R-143a and the
like.
Other objects and advantages of this invention will become apparent
from the following description and the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIGS. 1A and 1B show a FREON gas-permeation tester as used in the
examples, wherein 1 refers to a stainless steel cup, 2 to a
stainless steel lid, 3 to a punching board having a permeation area
of 1.16 cm.sup.2, 4 to a test piece of 2 mm in thickness, and 5 to
a bolt and 6 to a nut. FIG. 1A shows a frontal view of the
stainless steel lid of the FREON gas-permeation tester and FIG. 1B
shows an exploded side view of the FREON gas-permeation tester.
According to this invention, there is provided a thermoplastic
elastomer composition which comprises (a) 20 to 70 parts by weight
of a polyamide and (b) 80 to 30 parts by weight of a butyl rubber
modified with a functional-group-containing compound having at
least one group selected from a carboxyl group, an acid anhydride
group and an epoxy group as the functional group (hereinafter
referred to as the functional group-containing compound), the total
amount of the (a) and (b) components being 100 parts by weight (the
butyl rubber modified with the functional-group-containing compound
is hereinafter referred to as merely the modified butyl
rubber).
The polyamide (a) used in this invention includes nylon 6, nylon
6,6, nylon 11, nylon 12, nylon 6,9, nylon 6,10, nylon 4,6, nylon
6,12 and the like, among which nylon 11, nylon 12, nylon 6 and
nylon 4,6 are preferable and nylon 11 and nylon 12 are more
preferable.
The polyamide (a) may also be a polyamide obtained by
copolymerizing different monomers, namely a polyamide elastomer
synthesized by condensation of a polyether with a polyamide.
The modified butyl rubber (b) used in this invention is a butyl
rubber having, as a modifying group, a carboxyl group, an acid
anhydride group and/or an epoxy group. The modified butyl rubber
may be prepared by (1) a method which comprises adding, to a butyl
rubber or a halogenated butyl rubber, a functional-group-containing
compound selected from an .alpha.,.beta.-ethylenically unsaturated
carboxylic acid, an .alpha.,.beta.-ethylenically unsaturated
carboxylic anhydride, an .alpha.,.beta.-ethylenically unsaturated
carboxylic epoxide and an alkenyl glycidyl ether in the presence of
a peroxide, (2) a method which comprises adding, to a butyl rubber,
an alkali metal such as lithium, potassium, sodium or the like, and
then adding thereto a functional group-containing compound selected
from an .alpha.,.beta.-ethylenically unsaturated carboxylic acid,
an .alpha.,.beta.-ethylenically unsaturated carboxylic anhydride,
an .alpha.,.beta.-ethylenically unsaturated carboxylic epoxide and
an alkenyl glycidyl ether or (3) a method which comprises
dehydrohalogenating a halogenated butyl rubber with a
dehydrohalogenating agent such as a metal which has been subjected
to metal alcoholate-reduction, ZnO/RCOOH, (RCOO).sub.2
-Zn/RCOOH/CaO in which R is an alkyl group having 1 to 8 carbon
atoms, an aralkyl group or an aryl group (the same applies
hereinafter), CuO, (RCOO).sub.2 -Zn or the like to prepare a
conjugated diene unit-containing butyl rubber and then adding
thereto a functional-group-containing compound selected from an
.alpha.,.beta.-ethylenically unsaturated carboxylic acid, an
.alpha.,.beta.-ethylenically unsaturated carboxylic anhydride, an
.alpha.,.beta.-ethylenically unsaturated carboxylic epoxide and an
alkenyl glycidyl ether.
The modified butyl rubber (b) used in this invention is preferably
prepared by the above method (3) in which the conjugated diene
unit-containing butyl rubber is used.
The method of preparing the conjugated diene unit-containing butyl
rubber is disclosed in U.S. Pat. No. 3,965,213, Japanese Patent
Application Kokai Nos. 48-08385, 53-42289 and 59-84901, Japanese
Patent Application Kokoku No. 57-14363 and the like.
The functional group-containing compound used for modification of a
butyl rubber in the preparation of the modified butyl rubber (b)
includes .alpha.,.beta.-ethylenically unsaturated carboxylic acids
such as maleic acid, acrylic acid, methacrylic acid, itaconic acid,
monoethyl maleate, fumaric acid, monoethyl fumarate, vinylbenzoic
acid, vinylphthalic acid, monoethyl itaconate, maleic monoanilide
and the like; .alpha.,.beta.-ethylenically unsaturated carboxylic
anhydrides such as anhydrides of the above-mentioned ethylenically
unsaturated carboxylic acids, for example, maleic anhydride and the
like; .alpha.,.beta.-ethylenically unsaturated carboxylic epoxides
such as glycidyl methacrylate, glycidyl acrylate, monoglycidyl
itaconate, diglycidyl itaconate and the like; and alkenyl glycidyl
ethers such as allyl glycidyl ether, vinyl glycidyl ether and the
like.
In the preparation of the modified butyl rubber used in this
invention, for example, the above-mentioned conjugated diene
unit-containing butyl rubber is reacted with the
functional-group-containing compound in the absence of a solvent or
in the presence of an organic solvent such as n-hexane, toluene,
cyclohexane, heptane, xylene or the like at a temperature of from
room temperature to 300.degree. C. In this reaction, a small amount
of an organic peroxide such as benzoyl peroxide or the like may be
used. This reaction may be conducted in a reactor provided with a
stirring blade, a Banbury mixer, a kneader or the like.
The amount of the carboxyl group, acid anhydride group and/or epoxy
group to be introduced into the butyl rubber is 1 to 50
milliequivalents, preferably 2 to 20 milliequivalents, per 100 g of
the butyl rubber. When the amount of the functional group
introduced is too small, the blendability of the modified butyl
rubber (b) with the polyamide (a) becomes inferior and the
composition obtained becomes inferior in resistance to permeation
of hydrogen-containing FREON gases. When the amount is too high,
the composition obtained becomes inferior in flexibility.
The thermoplastic elastomer composition of this invention comprises
(a) a polyamide and (b) the modified butyl rubber as the essential
components, and the weight ratio of the (a) component to the (b)
component is 20/80-70/30, preferably 25/75-60/40, more preferably
30/70-55/45. When the amount of the modified butyl rubber (b) is
more than 80 parts by weight, the composition obtained has too low
strength to be used in rubber parts of a refrigerator and also is
inferior in oil resistance and moldability. On the other hand, when
the amount of the modified butyl rubber (b) is less than 30 parts
by weight, it is impossible to obtain the desired flexibility.
The composition of this invention may comprise, in addition to (a)
a polyamide and (b) the modified butyl rubber, not more than about
50 parts by weight, per 100 parts by weight of the modified butyl
rubber, of chloroprene, chlorinated polyethylene, polyisoprene,
natural rubber, an ethylene-propylene-diene copolymer rubber,
styrene-butadiene copolymer rubber, polybutadiene rubber,
chlorosulfonated polyethylene, an epichlorohydrin rubber, a
halogenated ethylene-propylene rubber, ethylene-butene copolymer or
the like.
The thermoplastic elastomer composition of this invention may
further comprise a filler in a proportion of preferably 20-200
parts by weight, more preferably 30-180 parts by weight, per 100
parts by weight of the composition.
The filler mentioned above includes carbon black, silica, calcium
carbonate and mica which have a surface area of 10 to 300 m.sup.2/
g (ASTM D3707) and a capability of absorbing dibutyl phthalate
(DBP) in a proportion of 20-150 cc/100 g and further finely divided
quartz, diatomaceous earth, zinc oxide, basic magnesium carbonate,
calcium metasilicate, titanium dioxide, talc, aluminum sulfate,
calcium sulfate, barium sulfate, asbestos, glass fiber, organic
reinforcing agents, organic fillers and the like. Particularly, the
above-mentioned carbon black, silica, calcium carbonate and mica
are preferred. Also, in the case of an inorganic filler, a
silane-coupling agent may be co-used to increase the modulus of
crosslinked product.
These fillers may be used alone or in combination of two or
more.
The thermoplastic elastomer composition of this invention may
further comprise other various additives which are conventionally
used. These additives may be added in the course of or after the
preparation of the thermoplastic elastomer composition of this
invention.
The thermoplastic elastomer composition may comprise, in any
combination, a dispersing assistant such as a higher fatty acid, a
metal salt or amine salt thereof: a plasticizer such as
polydimethylsiloxane oil, diphenylsilanediol, trimethylsilanol, a
phthalic acid derivative or an adipic acid derivative; a softening
agent such as a lubricating oil, process oil, coal tar, castor oil
or calcium stearate; an antioxidant such as a phenylenediamine, a
phosphate, a quinoline, a cresol, a phenol or a metal
dithiocarbamate; a heat-resisting agent such as iron oxide, cerium
oxide, potassium hydroxide, iron naphthenate or potassium
naphthenate; a coloring agent; an ultraviolet absorber; a
flame-retardant; an oil-resistance-improver; an antiscorching
agent; a tackifier; a lubricant and the like.
The thermoplastic elastomer composition of this invention can be
prepared by melt-mixing (a) a polyamide and (b) the modified butyl
rubber by means of an internal mixer such as roll, Banbury mixer,
press-kneader or the like or a kneading machine such as extruder or
the like.
In this case, it is possible to add a cross-linking agent for the
modified butyl rubber such as a combination of an organic peroxide
with a crosslinking assistant; a resin type crosslinking agent;
quinonedioxide; nitrobenzene; tetrachloroquinone; a diamin; a
combination of sulfur with a vulcanization accelerator and a
vulcanizing assistant; or the like, melt-mix them to prepare a
crosslinkable elastomer composition and thereafter subject the
resulting mixture to molding and crosslinking under the
conventional conditions to prepare a crosslinked product. Also,
ultraviolet crosslinking is possible.
The organic peroxide includes, for example, dicumyl peroxide,
2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3,
2,5-dimethyl-2,5-di(t-butylperoxy)hexane,
2,2'-bis(t-butylperoxy)-p-diisopropylbenzene, di-t-butyl peroxide,
t-butylbenzoate, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane,
2,4-dichlorobenzoyl peroxide, benzoyl peroxide, p-chlorobenzoyl
peroxide, t-butylperoxybenzoate, di-t-butylperoxyisophthalate and
the like, and preferred is dicumyl peroxide.
In the crosslinking with the organic peroxide, a difunctional vinyl
monomer may be used as a crosslinking assistant, and the
crosslinking assistant includes ethylene dimethacrylate,
1,3-butylene dimethacrylate, 1,4-butylene dimethacrylate,
1,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate,
1,4-butanediol diacrylate, 1,6-hexanediol diacrylate,
2,2'-bis(4-methacryloyldiethoxyphenyl)propane, trimethylolpropane
trimethacrylate, pentaerythritol triacrylate, divinylbenzene,
N,N'-methylenebisacrylamide, p-quinonedioxime,
p,p'-dibenzoylquinonedioxime, triazinedithiol, triallyl cyanurate,
triallyl isocyanurate, m-phenylene bismaleimide, a silicone oil
having a large vinyl content, and the like.
The resin type crosslinking agent includes alkylphenol-formaldehyde
resins, brominated alkylphenolformaldehyde resins and the like.
Also, an organic crosslinking agent such as quinonedioxime,
nitrobenzene, tetrachloroquinone or the like may be used in some
cases.
The diamine includes hexamethylenediamine, tetramethylenediamine,
3,3'-diphenylmethanediamine, 3,3'-dicyclohexylmethanediamine and
the like.
In a blend system comprising sulfur, a vulcanizing accelerator and
a vulcanizing assistant, the vulcanizing accelerator includes
guanidines, thioureas, thiazoles, dithiocarbamates, xanthates and
thiurams, and a mixing accelerator is also used.
The vulcanizing assistant, namely, a vulcanization-accelerating
assistant or an activator, includes metal hydroxides such as zinc
oxide, magnesium oxide and the like; a metal hydroxide such as
calcium hydroxide or the like; fatty acids such as stearic acid,
lauric acid, oleic acid and the like, and the
vulcanization-accelerator is used in such an amount as used in
conventional rubber blending.
The amount of the crosslinking agent or the crosslinking assistant
blended is 0.01 to 10 parts by weight, preferably 0.05 to 5 parts
by weight, per 100 parts by weight of the modified butyl rubber.
When the amount is too small, the crosslinking density of the
rubber component becomes low and the composition becomes inferior
in mechanical strength and resistance to permeation of
hydrogen-containing FREON gases. When the amount is too large, the
crosslinking density of the rubber component becomes high and the
elongation of the resulting composition becomes low.
The thermoplastic elastomer composition of this invention is
excellent in resistance to permeation of hydrogen-containing FREON
gases and, utilizing this characteristic feature, can be
appropriately used in rubber parts of a refrigerator in which FREON
gases, particularly hydrogen-containing FREON gases, are used, the
rubber parts including, for example, a hose, a packing, a sealant
and the like. For example, the hose and the packing may have a
layer composed of the thermoplastic elastomer composition of this
invention at a portion at which they contact with the refrigerant
used in a refrigerator.
This invention is further explained in more detail below referring
to Examples. In the Examples, various measurements were conducted
according to the following methods.
Physical properties of crosslinked product: Evaluated according to
JIS K6301.
Oil resistance: Measurement was effected at 100.degree. C. for 70
hours according to JIS K6301 using a JIS No. 3 oil.
Low-temperature resistance: Evaluated by a Gehman torsion test.
FREON gas permeability: A rubber composition was kneaded with the
compounding recipe shown in Table 1 or 2, and then vulcanized to
prepare a disk-shaped sheet having a thickness of 2 mm and a
diameter of 50 mm, after which the sheet was subjected to a FREON
gas permeation test using a FREON gas permeation tester as shown in
FIG. 1.
EXAMPLES 1-15 AND COMPARATIVE EXAMPLES 1-5
Preparation of Modified Butyl Rubber
Modified Butyl Rubber A
In a 3-liter flask, 100 g of chlorinated butyl rubber having a
chlorine content of 1.2% by weight (JSR Butyl 1068, a trade name of
Japan Synthetic Rubber, Co., Ltd.) was dissolved in 1,000 g of
toluene in a nitrogen gas stream.
Subsequently, 3 g of zinc oxide and 2 g of 2-ethylhexanoic acid
were added to the resulting solution, and thereafter, the resulting
mixture was subjected to reaction for 2 hours under reflux
conditions while removing water. The conjugated diene content of
the resulting polymer was 1 mole. Incidentally, the conjugated
diene content was determined by an ultraviolet ray-absorption
analysis.
The conjugated diene unit-containing butyl rubber was mixed with
maleic anhydride in a proportion of 0.5% by weight based on the
weight of the polymer (5 milliequivalents/100 g of polymer) at
150.degree. C. for 5 minutes in a 250-cc Brabender mixer to obtain
a maleic anhydride-modified butyl rubber.
The amount of the maleic anhydride added to the polymer was 0.4% by
weight.
Modified Butyl Rubber B
The same procedure as in the preparation of Modified Butyl Rubber A
was repeated, except that the amount of maleic anhydride was varied
to 2% by weight based on the weight of the polymer (20.4
milliequivalents/100 g of polymer), to obtain a maleic
anhydride-modified butyl rubber.
The amount of the maleic anhydride added to the polymer was 1.5% by
weight.
Modified Butyl Rubber C
The same procedure as in the preparation of Modified Butyl Rubber A
was repeated, except that the amount of maleic anhydride was varied
to 0.2% by weight based on the weight of the polymer (2
milliequivalents/100 g of polymer) to prepare a maleic anhydride
modified butyl rubber.
The amount of the maleic anhydride added to the polymer was 0.2% by
weight.
Modified Butyl Rubber D
The same procedure as in the preparation of Modified Butyl Rubber A
was repeated, except that 2.0% by weight of methacrylic acid (23.3
milliequivalents/100 g of polymer) was substituted for the 0.5% by
weight of maleic anhydride and the mixing was conducted at
150.degree. C. for 20 minutes, to obtain an acrylic acid-modified
butyl rubber.
The amount of the acrylic acid added to the polymer was 0.8% by
weight.
Modified Butyl Rubber E
The same procedure as in the preparation of Modified Butyl Rubber A
was repeated, except that 2.0% by weight of glycidyl methacrylate
(14 milliequivalents/100 g of polymer) was substituted for the 0.5%
by weight of maleic anhydride and the mixing was conducted at
150.degree. C. for 20 minutes, to obtain a glycidyl
methacrylate-modified butyl rubber.
The amount of the glycidyl methacrylate added to the polymer was
0.7% by weight
Modified Butyl Rubber F
To 100 parts by weight of a butyl rubber (JSR IIR 365, a trade name
of Japan Synthetic Rubber Co., Ltd.) were added 0.5 part by weight
of maleic anhydride and 0.3 part by weight of an organic peroxide
(dicumyl peroxide), and the resulting mixture was subjected to
mixing at 150.degree. C. for 15 minutes to obtain a maleic
anhydride-modified butyl rubber. The amount of the maleic anhydride
added to the polymer was 0.3% by weight.
Preparation of Composition and Crosslinked Product
(1) Nylon 11 (RILSAN BESNO, a trade name of TORAY INDUSTRIES, INC.)
and nylon 12 (RILSAN AESNO, a trade name of TORAY INDUSTRIES, INC.)
as polyamides and one of the Modified Butyl Rubbers A to E as the
modified butyl rubber were melt-mixed with the compounding recipe 1
shown in Table 1 in an internal mixer (HAAKE RHEOCORD SYSTEM 40
RHEOMIX MIXER 3000 manufactured by Haake Buchler) at 200.degree. C.
for 10 minutes, and the resulting mixture was pressed at
200.degree. C. for 10 minutes by an electrically heated press to
prepare a sheet of 2 mm (thickness).times.20 mm (width).times.20 mm
(length).
In Comparative Example 5, the compounding recipe 2 shown in Table 2
was used.
The sheets thus obtained were evaluated for physical
properties.
The results obtained are shown in Table 3.
TABLE 1 ______________________________________ Compounding recipe 1
(parts by weight) Methy- lene-bis- Di- Sam- Ny- Ny- Modified Carbon
cyclo- cumyl Mag- ple lon lon butyl black hexyl- pero- nesium No.
11 12 rubber N339 amine xide oxide
______________________________________ 1 50 -- A (50) -- 2 -- -- 2
70 -- A (30) -- 2 -- -- 3 40 -- A (60) -- 2 -- -- 4 -- 50 A (50) --
2 -- -- 5 50 -- A (50) 10 2 -- -- 6 50 -- A (50) -- -- 0.5 -- 7 50
-- B (50) -- 2 -- -- 8 50 -- C (50) -- 2 -- -- 9 50 -- D (50) -- 2
-- -- 10 50 -- E (50) -- 2 -- -- 11 50 -- F (50) -- 2 -- -- 12 50
-- A (50) -- -- -- 5 13 50 -- A (50) -- -- -- -- 14 50 -- JSR -- 2
-- 5 Butyl 1068 (50) 15 15 -- A (85) -- 2 -- -- 16 80 -- A (20) --
2 -- -- 17 100 -- -- -- -- -- --
______________________________________
TABLE 2 ______________________________________ Compounding receipt
2 100 parts by weight NBR (JSR N222L, a trade name of Japan
Synthetic Rubber Co., Ltd.) MT black 50 parts by weight SRF black
80 parts by weight Zinc oxide (ZnO) 5 parts by weight Stearic acid
1 parts by weight Polyester-based plasticizer*.sup.1 2 parts by
weight Antioxidant*.sup.2 0.5 parts by weight Sulfur 1.0 parts by
weight Vulcanizing accelerator*.sup.3 0.4 parts by weight NOCCELER
TT (tetramethylthiuram disulfide) NOCCELER CZ
(N-cyclohexyl-2-benzothiazyl 0.5 parts by weight sulfenamide)
______________________________________ Note: *.sup.1 RS 107, a
trade name of Adeka Argus Chemical Co., Ltd. *.sup.2 NOCRAC 810NA,
a trade name of Ohuchishinko Kagaku Kogyo K.K. for
Nphenyl-N'-isopropyl-p-phenylene diamine. *.sup.3 Products of
Ohuchishinko Kagaku Kogyo K.K. Vulcanization: Pressvulcanized at
150.degree. C. for 20 minutes.
TABLE 2
__________________________________________________________________________
FREON gas permeability 100% Tensile Elonga- Resist- Low temp. (Kind
of Modulus strength tion Hard- ance resistance FREON gas) Sample
(M.sub.100) (T.sub.B) (E.sub.B) ness .DELTA.V T.sub.5 /T.sub.10 (mg
.multidot. mm/ No. (kg/cm.sup.2) (kg/cm.sup.2) (%) (H.sub.S) (%)
(.degree.C.) cm.sup.2 .multidot. day)
__________________________________________________________________________
Example 1 1 210 350 270 99 8.0 <-70/<-70 12 (R22) 2 2 240 360
250 100 7.0 -70/<-70 8 (R22) 3 3 170 220 220 95 11.0 -55/<-70
15 (R22) 4 4 205 330 240 98 8.0 -67/<-70 14 (R22) 5 5 250 300
240 99 6.0 -67/<-70 9 (R22) 6 6 220 290 220 99 7.5 -67/<-70
13 (R22) 7 7 280 360 270 99 6.0 -68/<-70 8 (R22) 8 8 160 210 220
98 12.0 <-70/<-70 16 (R22) 9 9 155 205 180 99 13.0
<-70/<-70 25 (R22) 10 10 152 195 185 98 15.0 <-70/<-70
27 (R22) 11 11 165 200 190 99 13.0 <-70/<-70 20 (R22) 12 12
210 300 220 99 10.0 <-70/<-70 12 (R22) 13 13 -- -- -- -- --
-- 3 (R134a) 14 14 -- -- -- -- -- -- 5 (R142b/R22 = 50/50) 15 15
171 230 220 99 13.0 <-70/<-70 20 (R22) Comp. Example 1 14 154
193 160 99 11.0 <-70/<-70 42 (R22) 2 15 25 80 120 87 21.0
-47/-57 85 (R22) 3 16 270 390 320 100 4.5 Unmeasure- 8 (R22) able 4
17 350 420 350 100 3.1 Unmeasure- 7 (R22) able 5 NBR 73 185 350 85
8.0 -10/<-14 12 (R12)
__________________________________________________________________________
As is clear from Table 3, the present compositions in Examples 1 to
15 are superior in resistance to permeation of hydrogen-containing
FREON gases to the compositions in Comparative Examples 1 and 2,
and have a good balance of low-temperature resistance and tensile
characteristics.
In Comparative Examples 3 and 4, the composition are rich in nylon
and consists of nylon alone, respectively, and hence, are inferior
in low-temperature resistance and not suitable for use in vibration
parts. Comparative Example 5 is for showing the FREON
gas-permeability of a nitrile rubber (acrylonitrile-butadiene
rubber, NBR) composition using FREON gas R-12 and the physical
properties of the nitrile rubber composition.
It is seen that the hydrogen-containing FREON gas-permeabilities of
the present compositions in the Examples are equivalent to the
hydrogen-free FREON gas-permeability of the NBR composition, and
the low-temperature resistance, oil resistance and tensile
characteristics of the present composition are also equivalent to
those of the NBR composition.
* * * * *